Is smoke sim broken in 2.9 ? (simulation not refreshing)
There are known issues with refreshing a smoke simulation (and liquid) after changes (eg, see https://developer.blender.org/T77170. The best solution I’ve found is to click in the Resolution property, then hit Enter (so you're effectively changing the Resolution to the same value it's already set to). This effectively resets the whole simulation under most circumstances - then just re-play from the start again.
The ‘hires’ has become ‘Noise’. Enable the 'Noise' checkbox in the properties and adjust the settings.
Please clarify what you mean is wrong with the rendering of smoke in Eevee - maybe ask a separate question for that. However, it could just be that the default Volumetrics render settings are not suitable for your domain. In the first instance, try reducing the End until the most distant part of your volume justs starts to clip, then adjust the Start until the nearest part of your domain just starts to clip. This will concentrate the passes into the volumetric domain for sharpest render results. You can then try reducing the Tile Size and increasing the Samples to further refine the render. You might also want to switch on and adjust the Volumetric Shadows.